The most common material historically and currently used in concrete forms is wood. Recently, other alternative materials have been experimented with and used due to the limitations that wood as a material possesses. Such materials have included polyurethane and other plastics materials. Most of these prior art attempts to use and actual prior use of polyurethane and other plastics material in concrete forms involve the use of a high density plastic material having a relatively poor insulating ability rather than a low density material with excellent insulating qualities. The high density material is employed because it is stronger than the low density material. The structural arrangements of these prior art attempts and uses require that the higher strength material may be employed.
Some concrete forms using polyurethane or other plastics materials employ a low density material. However, these prior forms have involved radically new form configurations which of course radically change the configuration of the resulting walls which make the walls incompatible with most conventional building methods. The new configurations are necessary in order to use a low density polyurethane or other plastic material.
Some of these prior embodiments use preformed blocks of the high density plastic material that are manufactured off the construction site and transported thereto. These blocks are shaped very similar to conventional concrete blocks with vertical holes therethrough. To form a wall, the blocks are stacked one on top of another and the vertical holes filled with concrete.
There, of course, are many variations of the above. Some of the prior forms add panels on the exterior surfaces thereof for added structural stability and for added insulating capability. Still other prior art forms employ high density plastic panels tied directly together by metal ties to form a concrete form for receiving concrete and forming a concrete wall.
However, none of the prior art forms and form arrangements provide a form assembly which can employ a low density-high insulating ability foam plastic material that is compatible with most conventional building materials and methods. In all the formwork using foam plastic material known in the prior art, the foam plastic material that comprises the foam blocks or panels is either (1) comprised of a high density material (that has a low insulating ability) to withstand the forces involved in the pouring of the concrete therein and to have a strength necessary to support the forces exerted on the wall by the completed structure itself and the form work is in a conventional configuration; or (2) is comprised of a low density material but the forms are of a non-conventional configuration that is incompatible with most conventional building materials and methods.
In view of the above, it is clear that there exists a need in the art for a concrete formwork assembly which can be comprised of a material having a high insulating ability while at the same time possessing the strength qualities necessary to withstand the forces of concrete placement and hardening therein and subsequent structural load, without failure, and which is compatible with all conventional building materials and methods. It is the purpose of this invention to fulfill this need along with other needs apparent to those skilled in the art based on the following disclosure: